BIO 101 Exam 3 (Chapters 7-10)

The difference between Benign tumors and Malignant tumors?

Benign tumors are non-cancerous and do not spread to other parts of the body, while malignant tumors are cancerous and can invade nearby tissues and spread to distant sites.

The cell cycle is controlled by

checkpoints and regulatory proteins, including cyclins and cyclin-dependent kinases (CDKs).

Meiosis consists of two parts, what are they called?

meiosis I and meiosis II.

What are the meiosis phases in order?

prophase I, metaphase I, anaphase I, telophase I, cytokinesis I, prophase II, metaphase II, anaphase II, telophase II, and cytokinesis II.

Sex chromosomes determine

an individual's sex. in humans, they are X and Y chromosomes.

What is the purpose of Meiosis I?

Reduce the chromosome number in half from the starting cell.

What is the purpose of Meiosis II?

the separation of sister chromatids, resulting in four genetically different haploid cells from a diploid parent cell.

What is the difference between Mitosis and Meiosis?

Mitosis produces two genetically identical “daughter” cells from a single “parent” cell, whereas meiosis produces cells that are genetically unique from the parent and contain only half as much DNA. Mitosis is a type of cell division for somatic cells and for the asexual reproduction of unicellular eukaryotic cells. Meiosis is the type of cell division for the production of gametes in sexual reproduction.

Genetic variation in meiosis is primarily due to

crossing over and independent assortment of homologous chromosomes.

Mendel worked with pea plants because

they were easy to grow, had distinct traits, and could be easily crossbred.

Mendel discovered the principles of

Law of Dominance. Law of Segregation. Law of Independent Assortment, three principles of inheritance that described the transmission of genetic traits.

The Boveri–Sutton chromosome theory (also known as the chromosomal theory of inheritance) is

a fundamental unifying theory of genetics which identifies chromosomes as the carriers of genetic material.

What was the importance of Watson and Crick's discovery?

Their discovery of DNA's structure revolutionized our understanding of genetics and heredity.

Nitrogenous bases in DNA include

adenine (A), thymine (T), cytosine (C), and guanine (G).

Which nitrogenous bases pair together in DNA?

A pairs with T, and C pairs with G (in DNA.)

Prokaryotes divide by

binary fission, a simple form of asexual reproduction.

What is the difference between haploid and diploid?

Diploid cells contain two complete sets. Haploid organisms, on the other hand, only contain one complete chromosome set.

A duplicated chromosome consists of

two identical structures called chromatids, which are held together in the center by a structure called the centromere.

A homologous pair of chromosomes consists of

one chromosome from each parent.

Codons are found

on mRNA during translation.

What are the stop codons and what do they signal?

The stop codons (UAA, UAG, UGA) signal a halt to protein synthesis in the cell.

What is the universal start codon and what does it signal?

The start codon (AUG) signals the beginning of protein synthesis and codes for methionine.

Are codons universal for all organisms?

Yes. Codons are nearly universal in the genetic code among all organisms.

When mRNA is modified before it leaves the nucleus, what is splicing?

the introns are removed from the pre-mRNA, and the exons are stuck together to form a mature mRNA that does not contain the intron sequences.

When mRNA is modified before leaving the nucleus, what is added onto it?

A 5′ cap is added to the end of pre-mRNA while elongation is still in progress. The 5′ cap protects the mRNA from degradation and assists in ribosome binding during translation. A roughly 200 nucleotide-long poly-A tail is also added to the 3′ end of the pre-mRNA once elongation is complete.

Translation of an mRNA molecule by the ribosome occurs in what stages?

initiation, elongation, and termination processes.

What are human reproductive cells called? How many chromosomes do they have?

They are called gametes and have 23 chromosomes.

What is the name for human cells (all body cells EXCEPT sex cells)? How many chromosomes do they have?

They are called somatic cells and have 46 chromosomes.

During cell division, DNA condenses to become

Chromosomes

What is the centrosome? an organelle near the nucleus of a cell which contains the centrioles (in animal cells)

Mendel’s law of dominance states that

in a heterozygote, one trait will conceal the presence of another trait for the same characteristic.

Mendel’s law of segregation states that

during the formation of gamete, each gene separates from each other so that each gamete carries only one allele for each gene.

DNA is associated with proteins called histones, which are referred to as?

Chromatin

Each chromosome, when duplicated, consists of 2 __________ attached where?

sister chromatids (both are identical), attached at the centromere.

Are gametes and somatic cells made up of paired chromosomes?

Somatic cells have 46 chromosomes made up of 23 pairs. Gametes have 23 chromosomes and they are not in pairs.

What are the three main phases of the cell cycle?

Interphase, mitosis, and cytokinesis.

The interphase is made up of three phases, what are they?

The G1, S, and G2 phases.

What is the purpose of the G1 phase?

Preparation for cell division (often referred to as the growth phase)

What is the purpose of the S phase?

synthesis or replication of DNA.

What is the purpose of the G2 phase?

organelles and proteins necessary for cell division are produced.

What are the phases of Mitosis in order?

Prophase, prometaphase, metaphase, anaphase, telophase.

What is the purpose of mitosis?

the function of mitosis is to produce two identical daughter cells with exactly the same complement of chromosomes.

(The two main reasons for this to occur are:

Growth: Mitosis helps in the growth and development of a child into an adult.
Reproduction: Single-celled eukaryotic organisms such as amoeba reproduce by mitosis.)

In prometaphase, as the centrioles go in opposite directions, chromosomes do what?

attach to the mitotic spindle. They attach via the centromere.

During prophase, microtubules do what?

Are assembled into the mitotic spindle.

During prophase, what happens to chromatin?

They condense to become chromosomes.

During prophase, what happens to the nucleolus and nuclear envelope?

They break apart. They don’t disappear, they break up into fragments and move out of the way.

During metaphase, chromosomes are

lined up in the middle of the mitotic spindle. The mitotic spindle causes this.

During the telophase, the chromosomes

Go back into their looser form, Chromatin.

What happens during anaphase?

The sister chromatids split apart and move to opposite parts of the cell.

What two mitosis phases are opposites?

Anaphase and prophase.

During cytokinesis, the microfilament ________

“pinches off” or cinches and physically separates into two cells.

What are the duplicated cells called after the cell cycle?

Daughter cells.

What is the main difference between plant and animal cell cycles?

The process of cytokinesis is different since plants have cell walls that cant be pinched apart, so they need to build a new cell wall.

In regard to the mitotic spindle, what is the difference between plant and animal cell cycles?

Plants have centrosomes but not centrioles, but still form the mitotic spindle.

What is the term for animal cytokinesis?

Cleavage furrow.

What forms the cell plate?

Vesicles.

What is the formation of a new cell wall called in plant cytokinesis?

The formation of a cell plate.

When does cytokinesis begin in the cell cycle?

Cytokinesis occurs at the same time as the telophase.

What is binary fission?

a type of asexual reproduction/cell division typically observed in prokaryotes (bacteria) and a few single-celled eukaryotes.

When does cytokinesis begin in the cell cycle?

Cytokinesis occurs at the same time as the telophase.

What are gametes?

Human reproductive cells.

What are somatic cells?

Human cells that are NOT sex-related.

When Chromatin tightens what does it become?

Chromosomes

What is the organelle near the nucleus of a cell which contains the centrioles (in animal cells)?

Centrosome

What are sister chromatids?

The identical copies formed by the DNA replication of a chromosome.

What is a centromere?

The center of a chromosome that links a pair of sister chromatids together during cell division.

Interphase, mitosis, and cytokinesis are phases of what?

The cell cycle.

The G1, S, and G2 phases make up what?

The interphase.

The process of replicated chromosomes being split into two new nuclei is called what?

Mitosis

In prometaphase, as the centrioles go in opposite directions, chromosomes do what?

attach to the mitotic spindle. They attach via the centromere.

During prophase, microtubules are?

Assembled into the mitotic spindle.

During prophase, what happens to chromosomes?

They condense.

During prophase, which organelles break apart into fragments?

The nucleolus and nuclear envelope.

During metaphase, chromosomes are

lined up in the middle of the mitotic spindle. The mitotic spindle causes this.

During the telophase, which organelles reappear and disappear?

The nuclear envelope and nucleolus reappear, and the mitotic spindle disappears.

What is the mitotic spindle?

fibers that are formed from a cell's centrioles that aid in the cell cycle.

What are daughter cells?

cells that are the result of a single dividing parent cell.

What is cleavage furrow?

complex structures made up of microfilaments that aide in the final separation of the cells into two identical daughter cells.

What is a cell plate?

The structure formed when plant cells split into two by building new structures down the mid-section of the cell.

Monohybrid cross is used to study the inheritance of how many alleles?

a single pair of alleles

Dihybrid cross is used to study the inheritance of how many alleles?

2 different alleles

What are the ribosome subunits and their function?

Ribosomes consist of large and small subunits. The large subunit contains the A (aminoacyl) site, P (peptidyl) site, and E (exit) site. tRNA molecules bind at the A site (accepts incoming amino acids), P site (holds the growing peptide chain), and E site (where tRNA exits the ribosome).

tRNA molecules bind to

the ribosome in a solvent-accessible channel at the subunit interface.

What are the tRNA binding sites?

Three tRNA binding sites, the aminoacyl site (A site), peptidyl site (P site), and exit site (E site), have been identified on both the large and small subunit.

A heterozygous x heterozygous monohybrid cross results in a genotypic ratio of

1:2:1 (homozygous dominant to heterozygous to homozygous recessive)

A benign tumor is

a non-cancerous mass of cells that does not invade nearby tissues or spread to other parts of the body.

A malignant tumor is

a cancerous mass of cells that can invade nearby tissues and potentially spread to other parts of the body.

Metastasis refers to

the spread of cancer cells from the primary site to other parts of the body through the bloodstream or lymphatic system.

Gonads are

reproductive organs that produce gametes (sex cells), such as testes in males and ovaries in females.

Sex cells are

specialized cells (sperm in males and eggs in females) that carry genetic information and are involved in sexual reproduction.

Autosomes are

non-sex chromosomes, responsible for carrying genetic information unrelated to an individual's sex.

Syngamy is

the fusion of two gametes (sperm and egg) during fertilization.

A zygote is

the diploid cell formed by the fusion of sperm and egg during fertilization.

Synapsis is

the pairing of homologous chromosomes in prophase I of meiosis

Crossing over is

the exchange of genetic material between homologous chromosomes during prophase I

Homologous chromosomes are

chromosomes which contain the same genes in the same order along their chromosomal arms.

Oogenesis is

the process of egg cell formation in females.

Spermatogenesis is

the process of sperm cell formation in males.

Mendel’s law of independent assortment states that

the alleles of two (or more) different genes get sorted into gametes independently of one another during metaphase I, allowing for the production of gametes with many different assortments of homologous chromosomes.

Parthenogenesis is

a type of asexual reproduction in which an egg develops into an individual without fertilization.